cmake cuDNN find package

Reused from Caffe 2 (Apache Licensed)

[Link](https://github.com/caffe2/caffe2/blob/master/cmake/Modules/FindCuDNN.cmake)

cmake/Modules/FindCUDNN.cmake

+# - Try to find cuDNN
+#
+# The following variables are optionally searched for defaults
+#  CUDNN_ROOT_DIR:            Base directory where all cuDNN components are found
+#
+# The following are set after configuration is done:
+#  CUDNN_FOUND
+#  CUDNN_INCLUDE_DIRS
+#  CUDNN_LIBRARIES
+#  CUDNN_LIBRARY_DIRS
+
+include(FindPackageHandleStandardArgs)
+
+set(CUDNN_ROOT_DIR "" CACHE PATH "Folder contains NVIDIA cuDNN")
+
+find_path(CUDNN_INCLUDE_DIR cudnn.h
+    HINTS ${CUDNN_ROOT_DIR} ${CUDA_TOOLKIT_ROOT_DIR}
+    PATH_SUFFIXES cuda/include include)
+
+find_library(CUDNN_LIBRARY cudnn
+    HINTS ${CUDNN_ROOT_DIR} ${CUDA_TOOLKIT_ROOT_DIR}
+    PATH_SUFFIXES lib lib64 cuda/lib cuda/lib64 lib/x64)
+
+find_package_handle_standard_args(
+    CUDNN DEFAULT_MSG CUDNN_INCLUDE_DIR CUDNN_LIBRARY)
+
+if(CUDNN_FOUND)
+	# get cuDNN version
+  file(READ ${CUDNN_INCLUDE_DIR}/cudnn.h CUDNN_HEADER_CONTENTS)
+	string(REGEX MATCH "define CUDNN_MAJOR * +([0-9]+)"
+				 CUDNN_VERSION_MAJOR "${CUDNN_HEADER_CONTENTS}")
+	string(REGEX REPLACE "define CUDNN_MAJOR * +([0-9]+)" "\\1"
+				 CUDNN_VERSION_MAJOR "${CUDNN_VERSION_MAJOR}")
+	string(REGEX MATCH "define CUDNN_MINOR * +([0-9]+)"
+				 CUDNN_VERSION_MINOR "${CUDNN_HEADER_CONTENTS}")
+	string(REGEX REPLACE "define CUDNN_MINOR * +([0-9]+)" "\\1"
+				 CUDNN_VERSION_MINOR "${CUDNN_VERSION_MINOR}")
+	string(REGEX MATCH "define CUDNN_PATCHLEVEL * +([0-9]+)"
+				 CUDNN_VERSION_PATCH "${CUDNN_HEADER_CONTENTS}")
+	string(REGEX REPLACE "define CUDNN_PATCHLEVEL * +([0-9]+)" "\\1"
+				 CUDNN_VERSION_PATCH "${CUDNN_VERSION_PATCH}")
+  # Assemble cuDNN version
+  if(NOT CUDNN_VERSION_MAJOR)
+    set(CUDNN_VERSION "?")
+  else()
+    set(CUDNN_VERSION "${CUDNN_VERSION_MAJOR}.${CUDNN_VERSION_MINOR}.${CUDNN_VERSION_PATCH}")
+  endif()
+
+  set(CUDNN_INCLUDE_DIRS ${CUDNN_INCLUDE_DIR})
+  set(CUDNN_LIBRARIES ${CUDNN_LIBRARY})
+  message(STATUS "Found cuDNN: v${CUDNN_VERSION}  (include: ${CUDNN_INCLUDE_DIR}, library: ${CUDNN_LIBRARY})")
+  mark_as_advanced(CUDNN_ROOT_DIR CUDNN_LIBRARY CUDNN_INCLUDE_DIR)
+endif()

src/ngraph/CMakeLists.txt

@@ -90,6 +90,13 @@ if(USE_CUDA)
           "Please select a correct compiler version\n"
           )
       endif()
+    find_package(CUDNN 5 QUIET)
+    if(NOT CUDNN_FOUND)
+       message(WARNING
+          "If cuDNN is installed, try setting -DCUDNN_ROOT_DIR"
+          "Not compiling with CUDA. Suppress this warning with -DUSE_CUDA=OFF")
+          set(USE_CUDA OFF)
+    endif()
   else()
     message(WARNING "Not compiling with CUDA. Suppress this warning with -DUSE_CUDA=OFF")
     set(USE_CUDA OFF)